Pot type burner apparatus



Jan. 23, 1962 K. s. JENSON 3,017,924

POT TYPE BURNER APPARATUS Filed Dec. 24, 1958 2 Sheets-Sheet 1 Z II I It I 2 +51 M j jmfmzw 9 jZ fiezzrzell? 5-J2IZSOIZ f M, 6 MW Jan. 23, 1962 K. s. JENSON POT TYPE BURNER APPARATUS 2 Sheets-Sheet 2 Filed Dec. 24, 1958 if; 23 1%. Z

7 a w w Stat BfilYfiZd Patented Jan. .23, 1962 3,017,924 PUT TYPE BURNER AIPARATUS Kenneth S Jonson, Wisconsin Rapids, Wis, assignor to Preway, Inc, a corporation of Wisconsin Filed Dec. 24, 1958, er. No. 782,887 4 Claims. (Cl. 158-91 This invention relates to burner apparatus, and more particularly to burnersof the open pot type for burning liquid fuel.

It is a general object of the invention to provide a new and improved pot-type burner apparatus.

A more specific object is to provide a new and improved ignition means for pot-type burners.

Another object is to provide in a pot-type burner apparatus having an electric igniter element, a new and improved igniter cover means which reduces undesirable formations and collections of carbon on the igniter element and immediately adjacent parts and thereby increases efliciency of burner operation particularly during ignition and shut-down periods.

Other objects and advantages will become readily apparent from the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 is a plan view, partly broken away, of a pottype burner embodying the principles of the present invention;

FIG. 2 is a vertical sectional view through the center of the burner apparatus illustrated in FIG. 1 taken at about the line 2-2 of FIG. 1;

FIG. 3 is a fragmentary side elevational view of the burner apparatus illustrated in FIG. 1, taken from the left side as viewed in FIG. 1, and omitting an igniter element housing illustrated in FIGS. 1 and 2;

FIG. 4 is a fragmentary horizontal sectional view taken at about the line 4-4 of FIG. 2;

FIG. 5 is an end elevational view of the igniter element enclosure, together with wick, taken from the left as the enclosure is viewed in FIGS. 1, 2 and 4; and

FIG. 6 is a side elevational view of the igniter element enclosure illustrated in FIG. 5.

While an illustrative embodiment of the invention is shown in the drawings and will be described in detail herein, the invention is susceptible of embodiment in many different forms, and it should be understood that the present disclosure is to be considered as an exempli- =fication of the principles of the invention and is not intended to limit the invention to the embodiment illustrated. The scope of the invention will be pointed out in the appended claims.

This invention constitutes an improvement over the burner apparatus of the co-pending application of Kenneth S. Ienson and Frederick W. Suhr, filed February 19, 1958, as Serial No. 716,152, assigned to the assignee of this application.

Referring now to the drawings in more detail, the invention, as illustrated, is embodied in a burner apparatus including an open pot type burner 10. Fuel oil in a liquid state is supplied to the bottom of the burner pot through conduits 11 and 12 preferably by gravity flow from a flow control unit (not shown) in turn supplied by gravity from a suitable tank or reservoir (not shown). The flow control unit referred to is shown and described in more detail in the aforesaid co-pending application. In general, it includes an inlet valve controlling flow from the reservoir and in turn controlled by a level responsive device such as a flo-at which controls the level of fluid in the flow control unit and in the burner pot as well. Additionally, the flow control unit preferably includes anoutlet valve controlling flow to the burner pot under control of a thermostatic device which opens the outlet valve in response to a call for heat, and closes the outlet valve when the demand for heat is satisfied. With such a flow control unit, it will be understood that the burner apparatus is intended principally for use in an on-oflf type of operation wherein the burner is ignited when there is a call for heat and wherein the flame is completely extinguished when the demand for heat is satisfied.

The burner pot 10 includes a cylindrical side wall 15 and a bottom wall 16 including an outer annular upturned flange portion 17 which is suitably joined to the bottom edge of the side wall 15 as by welding. The side wall and the bottom well together define a generally cylindrical pot which is substantially open at the top. In the embodiment illustrated, the burner pot has a diameter of about 11 inches.

According to the invention, the bottom Wall 16 is formed with an annular depression or groove 1% which forms an annular fuel well concentrically disposed within the cylindrical burner pot and positioned approximately midway between the center of the pot and the pot side wall. The groove slopes from a shallow portion 19a at one side of the pot center, ther ight side as illustrated in FIGS. 1 and 2, to a deeper portion 1% at the opposite of the pot center, the deeper portion having a contsant depth for a substantial length of the groove as will appear best in FIG. 3. The shallow portion 19a is about inch deep, and the portion 19b is about 1 4 inches deep. The fuel inlet conduit 12 opens into the groove centrally of the deeper portion 19b. The groove is formed of a substantially vertical inner wall 19c and an outwardly and upwardly inclined outer wall 1%. The diameter of the inner wall 19c in a preferred embodiment is about 4 inches. The groove is about inch wide at the bottom and about inch wide at the top oil level.

The remaining portions of the bottom wall 16 include a central portion 21 which is conically shaped to slope upwardly toward the center of the pot from the inner edge of the annular well 19. The radially outer portion of the burner pot bottom wall slopes upwardly from the outer edge of the annular groove to the corner of the pot where it joins the side wall St) at substantially the level of the center of the pot.

The burner pot side wall 15 is provided with a plurality of air inlet openings arranged in horizontal, vertically spaced rows. Beginning at the bottom of the burner pot side wall and proceeding upwardly, there are six rows of air inlet openings 23 in which the openings are rather widely spaced horizontally in the rows. Adjacent the top of the pot there is a seventh row of openings 24 wherein the openings are closely spaced. In the embodiment illustrated, the bottom row of openings 23 is positioned about Z; inches from the bottom edge of the side wall, and thereafter upwardly, the rows 23 and the row 24 are vertically spaced apart on centers of 1 4 inches. In the row 23, the separate openings are spaced apart horizontally around the pot side wall on l inch centers. In the upper row 24, the openings are spaced on .273 inch centers. In each of the rows, the openings are .113 inch in diameter.

Preferably, the air inlet openings in the burner port side wall are formed in the side wall as described in the aforesaid co-pending application, and are sized and arranged to enable a predetermined flow of air into the pot to produce eflicient combustion under all circumstances of burner operation.

Near the upper end of the burner side wall 15, but spaced slightly therebelow, the side wall is provided with an inwardly extending annular lip or flange 26. This flange is turned inwardly from a short cylindrical sleeve 27 which may be welded or otherwise suitably secured to the side wall 15. The lip 26 is provided to direct any aomsee cool, unburned gases adjacent the side wall inwardly toward the center of the pot to insure complete combustion.

At the upper rim of the side wall 15, the pot is formed with a horizontally disposed, outwardly extending rim 28 having at its outer periphery an upwardly turned flange 29. As illustrated, the rim portion 28, 29 is formed integrally with the sleeve portion 27 which may be welded to the burner pot side wall. The outwardly extending rim portion 28, 29 facilitates handling of the pot and also affords a support means for an annular upper high fire ring of a conventional type, if such a ring is found desirable or necessary under peculiar conditions of operation. It should be understood, however, that in the preferred mode of operation, no high fire ring is necessary as the burner is capable of operation over a wide range of high fires without such a ring.

While the intended mode of operation described for the burner apparatus illustrated contemplates the use of ignition means and an on-off cycle of operation wherein the fire dies completely when there is no call for heat, and is ignited again when there is a demand for heat, provision is made for use of a low fire pilot ring in the burner pot if a low fire or pilot fire type of operation is desired wherein the fire is merely lowered rather than extinguished when there is no call for heat. Accordingly, somewhat above the low row of air inlet openings 23, low fire air baflie ring supporting pins 31 in the form of rivets or the like may be secured in the burner pot side wall to project radially inwardly to afford a support for a low fire pilot ring such as that illustrated at 33 in broken line. The ring 33 may be employed to add stability to a low fire where extended periods of pilot fire operation are contemplated, though no such ring is necessary with the contemplated mode of on-off operation.

Ignition of fuel in the burner pot is obtained by an igniter element 35 which comprises an elongated U- shaped element which may be electrically energized to supply heat which vaporizes fuel and heats the resultant vapor to the point of ignition. The ignited element projects through an opening 37 (FIG. 2) in the burner pot side wall where suitable gasket means (not shown) may be provided, and the end portion 35a of the igniter element overlies the fuel well 19 at one side of the center of the pot.

According to the invention, the igniter element 35 is housed in an enclosure which includes a hood or cover member 40 and a bottom closure member 41. The cover member 40 is of an inverted channel-shaped cross section, having upright side walls 43 with bottom edges parallel and adjacent the outer portion of the burner pot bottom wall 16. The side walls 43 extend from an inner end substantially even with the tip of the igniter element 35, outwardly to engage the burner side wall 15. At the outer end, the upright edges of the side walls are formed with laterally turned flanges 44 which abut against the burner pot side wall. The upper edges of the side walls 43 taper upwardly from the inner ends to the outer ends, and are joined by a top wall 45. Like the side walls, the top wall extends from an inner end substantially even with the igniter tip outwardly to the burner pot side wall. At the outer edge, the top wall is formed with an upwardly extending flange 46 which is joined to the flanges 44 and abuts the burner pot side wall 15. It will be understood that the lower edges of the side walls 43 conform to the shape of the burner pot bottom wall 16, and the flanges 44 and 46 fit the burner pot side wall so as to substantially enclose the igniter element at the top and the sides in a chamber which is open at the inner end adjacent the igniter tip.

The top wall of the cover member 40 is formed with a V-shaped recess 45a extending outwardly from the inner end of the top wall to permit circulation of air and oxygen around and underneath the igniter element. Centrally of the upwardly extending flange 46, it is formed with an upwardly projecting handle portion 48 which facilitates manipulation of the cover member. The cover member is retained in position in the pot by means of headed rivets as at 50 with the heads of the rivets spaced somewhat from the side wall 15 to receive the flanges 44 which may be inserted by moving the igniter cover member vertically downwardly between the rivets.

The bottom closure member 41 comprises an upwardly facing channel-shaped member having a bottom wall 52, and upwardly turned side flanges 53 which are preferably attached to the cover member side walls 43 as by screws illustrated at 54. The bottom wall 52 has a length approximately corresponding to the length of cover member side walls 43, and extends from an inner end adjacent the tip 35a of the igniter element outwardly substantially to the burner pot side wall 15. At the inner end, the bottom wall 52 includes a perforated tongue turned first upwardly as at 58 (FIG. 6) and then downwardly as at 59, the portion 59 being turned back upon the portion 58 and compressed to hold a doubled wick member 60 of suitable absorbent material which is positioned just inwardly of the igniter tip 35a and hangs into the fuel well 19 as seen best in FIG. 2.

The igniter element 35 is supported at its outer ends on a member 62 having a backwardly turned end portion 62a adapted to fit over the edge of a housing 63 secured to the outside of the burner pot side wall 15. The igniter element may be energized by suitable circuits including a pair of wires 64 and 65 connected respectively to the outer ends of the igniter element, the latter leading through a control switch 105, and both proceeding outwardly of the housing 63 through an access opening 67. The control switch is a commercially obtainable item of conventional construction which includes one movable switch contact of bimetal composition which is responsive to heat generated by the current flowing through the igniter circuit. The operation is such that the bimetal contact normally closes against a stationary contact, but after energization of the circuit for a short period of time bends to open the switch thereby deenergizing the igniter. After the switch is open for a short time, the bimetal cools and again closes to energize the igniter. In this manner the igniter is cycled between on and off conditions until such time as ignition is established in the burner pot. The switch 105 incorporates a bimetal disk which is responsive to the heat of combustion in the burner pot, and after ignition is established flexes to open the movable switch contact to thereby deenergize the igniter, and maintain the igniter deenergized so long as the burner remains in operation. As the circuits for controlling energization of the igniter element form no part of the present invention, further description of such circuits is unnecessary here.

In operation, liquid fuel in the well 19 rises up the wick 60. While the well 19 may not always be filled with liquid fuel, on descent of the fuel in the well the wick 60 retains a quantity of the liquid fuel, so that when the igniter element 35 is energized, the heat from this element vaporizes liquid fuel supplied by the wick 60, and heats the vapor thus formed to the point of ignition. At first, the flame is confined to a rather limited area immediately adjacent the wick and igniter element, but as the fire continues, the heat vaporizes additional liquid fuel in the well adjacent the flame until the flame spreads around the entire annular groove. The flame thus begun continues to burn at substantially the level of the fuel for a limited time while the flame grows higher and higher. As the fire grows and the pot becomes heated, the flame gradually rises in the pot through the successive levels of the horizontal rows of air inlet openings until finally the flame burns at the top of the pot. On burner shutdown, when the igniter is deenergized, the level of fuel in the well 19 gradually lowers after the fuel supply valve is closed until such time as all the fuel in the pot is burned out.

The improvements in the present construction over that illustrated in the aforesaid co-pending application include the widening outwardly of the fuel groove 19 to substantially twice the width in the previous construction. Further, the present construction includes the bottom cover member 41 and the wick member as.

Widening of the fuel well enables the circulation of increased quantities of air to support combustion of carbon residue during the shutting-off and cooling-down period of the operation cycle thereby to reduce carbon collection in the vicinity of the well. In the prior construction, without the bottom cover member 41, during the sooty stage of operation on shutting down the burner, the last smokey flame during burner operation deposited a layer of soot on the igniter element. On reenergizing the igniter element a layer of soot was loosened and this dropped from the igniter element into the fuel well in the immediate vicinity of the inlet. Over a period of time, such soot dropping into the fuel well continued until ignition failure would develop because of too much vaporization of fuel due to saturation of the soot and carbon collected immediately adjacent the igniter element. The provision of the bottom cover member 41, firstly, reduces the collection of carbon on the igniter element during the sooty stages on shutting down the burner. Secondly, the cover prevents any soot from falling into the fuel well when dislodged from the igniter element on reenergizing the same. The first result occurs because the bottom cover member 41 forms a barrier or shield between the dying, sooty flame and the igniter element. The second result occurs because the cover member 41 is positioned beneath the igniter element and catches any soot falling from the igniter element. Thirdly, any soot which does collect on the igniter element and then falls onto the bottom cover member 41 is substantially consumed during periods of burner operation and high fire as the igniter element enclosure 40, 41 provides a receptacle or chamber that is well aerated at high temperatures and is therefore conducive to the consumption of any soot that may drop from the igniter or burner parts onto the member 41. Fourth, the igniter cover member 41 serves to limit the amount of vaporization which may be produced by the igniter element and also limits the amount of vapor accessible to the igniter element to thereby reduce the concentration of vapor on burner start-up.

The wick 60 supplies liquid in limited quantities for vaporization by the igniter. Any carbon collecting on the wick or in the vicinity of the wick in the well 19 is now unobjectionable because such a collection of carbon would serve merely to function as the wick functions.

I claim:

1. In a burner apparatus for liquid fuels, a burner pot having a cylindrical side wall and a bottom wall having a concentric annular depression spaced approximately midway between the center of the pot and said side wall to provide a well for liquid fuel, means forming a fuel inlet to the fuel well, air inlet openings in said burner pot side wall, an igniter element projecting through the burner pot side wall including an end portion overlying the fuel well at one side of the center of the pot, an igniter element enclosure including spaced side walls extending along opposite sides of the igniter element from the burner pot side Wall to said igniter element end portion, a top wall over the igniter element having a length comparable to that of the enclosure side walls and having a V-shaped opening over said igniter element end portion, and a bottom wall under the igniter element having a length comparable to that of the enclosure side walls disposed between the igniter element and the fuel well to reduce the formation of soot on the igniter element on burner shutdown, a perforated tongue at the end of said bottom wall underlying said igniter element end portion and having spaced apart sections, and a wick attached to said perforated tongue between the sections thereof with a part exposed to said igniter element and hanging into said fuel well.

2. In a burner apparatus for liquid fuel, a burner pot having side walls and a bottom wall and open at the top, said bottom wall having a continuous depression therein surrounding the center of the pot and spaced between the center of the pot and the side walls, an igniter element projecting through a burner pot side wall and having an end portion overlying the fuel well at one side of the center of the pot, an igniter element enclosure including spaced side walls along opposite sides of the igniter element, a top wall over the igniter element and a bottom wall underlying substantially the entire portion of the igniter element disposed in the pot between said entire portion and the fuel well, said enclosure being closed at the outer end adjacent the burner pot side wall and open at the inner end adjacent said igniter element end portion to provide a chamber ventilated during combustion at high temperatures thereby to enable consumption of soot in the chamber, the inner ends of said enclosure top and side walls being disposed outwardly from the center of the pot at least as far as the inner end of the bottom wall so that the igniter element is shielded from collection of carbon during sooty stages of burner operation, and said enclosure bottom wall being horizontally disposed to a degree sufficient to catch and hold soot against falling into the fuel well.

3. In a burner apparatus for liquid fuels, a burner pot including a side wall and a bottom wall, a depression in said bottom wall spaced from said side wall providing a fuel well, an electric igniter element projecting through said side wall and having an end portion overlying said fuel Well for vaporizing liquid fuel and igniting the resultant vapor, an igniter element enclosure including spaced side walls along opposite sides of the igniter element, a top wall over the igniter element, and a bottom wall beneath the igniter element shielding the same from the fuel well, said enclosure being closed at the outer end adjacent the pot side wall and open at the inner end adjacent said igniter element end portion, and a wick attached to said enclosure adjacent the open end thereof and hanging into the fuel well, the inner ends of said enclosure top and side walls being disposed outwardly from the center of the pot at least as far as the inner end of the bottom Wall so that the igniter element is shielded from collection of carbon during sooty stages of burner operation.

4. In a burner for liquid fuel, a burner pot including a side wall and a bottom wall, a fuel well in the bottom wall of the pot, an electric igniter element projecting through said side wall into the pot and having an end portion over the fuel Well for vaporizing liquid fuel and igniting the resultant vapor, an igniter cover over the igniter element, a bottom closure wall between the well and the igniter element, closing the bottom of said cover and defining a chamber open only at the end adjacent said igniter element end portion, and a Wick attached to said bottom closure member adjacent said igniter element end portion and hanging into the fuel well, and said enclosure bottom wall being horizontally disposed to a degree sufficient to catch and hold soot against falling into the fuel well.

References Cited in the file of this patent UNITED STATES PATENTS 2,646,111 Long July 21, 1953 2,902,578 Johnson et al. Sept. 1, 1959 2,966,941 Breese et al Jan. 3, 1961 2,966,942 Breese et al. J an. 3, 1961 FOREIGN PATENTS 477,076 Canada Sept. 18, 1951 550,971 Belgium Sept. 29, 1956 

